Absolute of Cistus ladaniferus (Cistaceae) obtained from cistus concrete by ethanol extraction

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7-17 May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP. The substance is considered to be adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

2008

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on 15 and 16 November 2017 / signed on 15 May 2018

Type of method:

differential scanning calorimetry

Melting / freezing pt.:

< 4.9 °C

Atm. press.:

ca. 1 013 hPa

Remarks on result:

other:

Remarks:

Atmospheric pressure not specified, but assumed to be ambient. Potential delay of melting till approximately 18°C.

Results of the pre-test 1:

At room temperature, the test item was a green-brown very viscous, very sticky mass. At 4.9°C, the test item was more solid rarely piercable, but still pierceable (viscous mass). At -21.1°C and -80°C, the test item was solid like ice.

 

Results of the pre-test 2:

From 48°C the little thin wire began to sink in the surface, i.e. the beginning of a transition leading to a more flowable form of the substance was detected. At 73°C, the little thin wire was completely sank to the bottom, i.e. the end of a transition leading to a more flowable form of the substance was detected.

Results of the Main test using DSC method:

In all runs the mass of the crucibles was the same and the crucible was visually unchanged after the test.

All the values were evaluated with event marker function

In all the DSC measurements, no events were detected in the cooling down phase.

In the heating phase, two flat and broad endothermic peaks were detected.

The first one was in a range of -29.92 °C to 4.39 °C (243.23 K – 277.54 K).

In pre-test 1, we noted that the test item was solid after a storage time of 48 hours at -21.1 °C, whereas it was not frozen after a storage time of 48 hours at 4.9 °C. However, at this temperature, the test item was more solid, rarely pierceable, which may indicate that it is close to the beginning of the freezing.

4.9°C was very close to the ending temperature of the endothermic event observed by DSC. Therefore this event may be assigned to the melting of the test item.

 

The second endothermic event was in a range of 3.56 °C to 18.17 °C (276.71 K – 291.32 K).

This event might indicate a delay of meltingor a kind of transition leading to a form different from the original test item at room temperature.

Note: that is not unusual to observe flat and broad peaks and even more than one peak in this kind of complex UVCB substances.

 

As no freezing was observed during the cooling down phase, the events observed in the heating up phase of the DSC measurements were difficult to interpret without ambiguity.

No observations were made which might cause doubts on the validity of the study outcome. Therefore, the result of the study is considered valid.

Conclusions:

The melting point of test substance was determined to be below 4.9°C, with potential delay of melting till approximately 18°C.

Executive summary:

The melting range of the test substance was determined under GLP according to EU Method A.1 and OECD 102, using the DSC method. Two pre-tests were also conducted to interpret the results obtained with the DSC method.

Two DSC determinations and a replicate were conducted:

In the cooling down phase no event could be detected from 20 to -45°C. Therefore no signs of freezing of the test item could be detected.

In the heating up phase two flat and broad endothermic events were detected from -45°C to 95°C.

The first event was in a range of -29.92 °C to 4.39 °C (243.23 K – 277.54 K).

In the pre-test 1, the test item was not frozen after a storage time of 48 hours at 4.9°C whereas it was frozen at -21.1 °C.

Therefore, this event may be assigned to the melting of the test item.

 

The second endothermic event was in a range of 3.56 °C to 18.17 °C (276.71 K – 291.32 K).

This event might indicate a delay of meltingor a kind of transition leading to a form different from the original test item at room temperature.

As no freezing was observed during the cooling down phase, the events observed in the heating up phase of the DSC measurements were difficult to interpret without ambiguity. 

For that reason,the freezing and / or melting point ofthe test item has been stated as below 4.9°C (278.1 K) with potential delay of melting till approximately 18°C under these circumstances.

Note that in the pre-test 2, a transition leading to a more flowable form of the substance was detected between 48 and 73°C.

 

Description of key information

The melting point of the test item was considered to be < 4.9°C (278.1K), with potential delay of melting till approximately 18°C.

Note that the substance is flowable at a temperature of 73°C.

Additional information

A fully reliable GLP experimental study, conducted according to a recognized OECD/EC guidelines is available.

It is considered as a key study.